Exemplary embodiments of the present invention relate to a digital receiver of a mobile communication system of supporting multiple channels and multiple bands.
Generally, a digital front end serves to perform digital modulation and demodulation of an RF receiver performing signal processing of a radio frequency/intermediate frequency (RF/IF) end using digital or discrete time rather than performing the signal processing thereof using an analog circuit of the related art.
Most of the mobile communication system standards support multiple channel bands and various frequency bands are supported. As an example, a long term evolution (LTE) system standard supports various frequency bands, such as 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, or the like.
In the related art, when a single system supports multiple channel bands, a frequency band is narrow so as to all the channel bands in single hardware architecture and thus, the number of taps required in a channel filter is increased in inverse proportion thereto. In order to implement the channel filter, a multiplier that is the most complex arithmetic unit in a digital hardware is required. However, the number of taps is increased and the number of multipliers is also increased accordingly, such that complexity in implementing digital hardware may be increased.
In order to solve the problems, methods for preventing the number of multipliers from suddenly increasing by using a multi-stage channel filter have been used. However, since most of the methods are implemented by a finite impulse response filter, the methods also have a problem in that the required number of multipliers is increased according to a channel bands.
The above technology configuration is a background art for helping understanding of the present invention but does not mean the related art well-known in the art to which the present invention pertains.